Game racket frame



Sept. 9, 1952Y c. A. Low-:LL

GAME RACKET FRAME 2 SHEETS--SHEET 2 Filed Dec. 2, 1948 INVENTOR CLA/2am? A' l/'L BY M W A ORNEY LA UUUJU Patented Sept. 9, 1952 UNITED STATES PATENT OFFICE 2,610,056 GAME RACKET FRAME Clarence A. Lovell, S11mmit,rN.r.l. Application December 2, 1948, Serial No. 63,089 (c1. 27s-7s) 1 Claim.

The invention relates to the `construction of rackets for playing games such as tennis, squash, squash racquets, badminton, etc. More particularly, it relates to the manufacture of metal racket frames which can be strung with gut, nylon, silk, or any other suitable fibrous material, as well as with metal strings.

The disadvantages of the ordinary racket frame made of wood have long been recognized. For one thing, it is aifected by moisture and will warp. The racket usually must be kept in a waterproof case and be put into a clamp or lframe when not in use to help preserve its shape,

but notwithstanding such' precautions warping may, and frequently does, occur, making the racket of little further use. Another disadvantage of the Wood racket frame is that because of the rather low crushing strength of wood, the strings of the racket, being under considerable tension, will cut into the wood at the corners of the string openings at the points where the string turns at right angles along the outer surface of the frame. This may in time contribute to a lessening of the tension on the strings, necessitating more frequent re-stringing or decreasing the driving power or harming other playing characteristics of the racket.

These, and perhaps other, drawbacks of the ordinary wood racket frame, have led to various attempts to substitute metal for wood in making the frame. These attempts have been reasonably successful wherever steel strings have been used in place of gut or nylon. However, steel strings do not seem to have as desirable playing qualities as do gut and other fibrous string materials. On the other hand, the metal rackets heretofore offered have not been well suited to gut Stringing. Perhaps one reason for this is that in the case of tubular metal frames difficulty is encountered in avoiding abrasion and cutting of the strings at their points of contact with the edges of the thin metal walls of the frame even though embossed holes are used to minimize these effects. Whatever the reasons, it is a fact that wood rackets, with all their conceded disadvantages, are still in general favor with tennis players and other users of rackets.

It is a leading object of my invention to provide a racket frame construction which is especially adapted to be made of metal, and which also can be strung with gut, nylon, silk, or other material (as well as with metal strings, if desired) yet which permits the Stringing of gut and the like to be drawn up to high tension without danger of abrasion or cutting of the strings, so as to make a thoroughly practicable racket having a metal frame with gut or other fibrous Stringing, and having playing qualities similar to those of the most acceptable rackets now in use.

Another object is to provide a racket frame which facilitates the Stringing operation.

A still further object is to provide a racket frame which-has a smooth outer edge devoid of string openings, and a method of constructing such a racket.

Other objects and advantages will appear as the description proceeds.

In accordance with my invention, a racket frame of hollow tubular construction having a series of string openings around its inner perimeter, is provided with string guides connecting the string opening in pairs. In my preferred construction the string guides take the form of curved tubular elements connecting adjacent pairs of string openings, and these curved tubular .elements have two principal functions: (1) they constitute guides for Stringing the racket and 2) they serve as bearings against which the string is tensioned. In addition, these curved tubular elements strengthen the tubular frame itself. There is thus provided a racket frame construction having a series of curved passages, each extending from one pointl on the inner perimeter of the frame to another point on the inner perimeter of the frame whereby a string inserted at one point will be guided for emergence at another point. This construction makes it possible to have the` outer perimeter of the frame devoid of string openings, for inasmuch as the curved guide elements are located entirely within the tubular frame -of the racket, a smooth surface is preserved along the outside edge of the frame. This not only creates an improved appearance, but has the advantage of protecting the strings from the damage which might otherwise result from contact with court surfaces, such as that due to abrasion and moisture, as `could occur with ordinary rackets in which the strings extend to the outside of the frame.

One of the principal problems in manufacturing a tubular racket frame which has curved tubular string bearings within it, is to simplify the manufacturing steps sufliciently to enable it to be fabricated at a low enough cost to make the racket commercially practicable. In making a tennis racket frame having the conventional number of interlaced strings across its face, 42 string bearings must be provided. In accordance with my invention all of these string bearings are completely hidden within the frame, and the problem` from an assembly standpoint entails the construction and anchoring of these l2 string bearings on sub-assemblies. Accordingly my. invention in its overall aspect deals not only with the provision of an improved Y racket frame construction but also with a novel fabricating method. These and other features of my invention will now be described with reference to the particular preferred embodiments shown in the accompanying drawings in which:

Fig. l is a face view of a racket having a frame constructed in accordance with the principles of the invention in what I now consider to be its preferred form.

Fig. 2 is a side view of the same racket.

3 Figs. 3 and 4 are detail cross-sectional views taken as indicatedA at 3-3 and 4 4 in Fig. 1 but to an enlarged scale.

Figs. 5 and 6 are enlarged detail views of a portion of the frame sub-assembly, illustrating the. manner in which the curved tubular guiding ele-y ments or string bearings are aflixed to a strip which later will be bent into a closed loop and securedto the edges of the remainingV frame members to form the inner perimeter of the frame. Fig. 6 is a bottomiplan view of this subassembly, and Fig. 5 is a central vertical longitudinal' cross-sectional View of the assembly shown in Fig. 6 with the curved string bearings shown in side elevation.

Figs. 7 and 8 are further detail cross-sectional views. of portions. of the racket of Fig. 1'. These are central cross-sectional views taken parallel tothe face ofthe racket, Fig. 7 illustrating a section .atthe end of the frame (extreme left-hand end'ofFig. 1)., and Fig. 8 illustrating aY section at'the throat.

Figs. 9, 10.1and. 11 are detailv Views illustrating a modiiiedlframe` construction. and an alternative method off'assembling the curved string bearing elements. Fig. 9is 'a central cross-sectional view through a portionof the tubular frame in the plane of the face of the racket showing one of the-string bearing. elements in place and ready to be secured. Fig. l0` is a cross-section taken at'` right angles to Fig. .9, showing an intermediate positionof the string bearing element during its insertion into the-tubular frame. view. similar to Fig. 9, but showing. two of the stringv bearings secured in place in the completed racket frame.

Figs. 12 andlS are detail cross-sectional views illustrating one method of anchoring the strings whenaflengthof new string is put in to repair a racket without entirely re-stringing it.

Figs..l4and15 are detailcross-sectional views showing my presently preferred method of anchoringthe strings when the racket is initially str-ungor completelyV re-strung.

Figs. 16 and-17 are diagrams illustrating the string arrangement employed in the racket of Figpl, Fig.V 16V showing what we may refer to as the longitudinal Stringing, and Fig. 17 the transverse Stringing.

. My preferred racket construction illustrated in Figs. 1 to 8 inclusive comprises in its general arrangement a pair of complementary curved membersgenerally U-shaped in cross-section and a' mating inner loop section 2li secured to the edges of the U-shaped members I8, I9. These three'v members, together with the associated string guides and gusset plates, form the head ofthe racket frame. The complementary curved members I8,- I9 are reversely curved adjacent the throat of the racket and terminate in straight parallel'adjacent sections 2I, 22 forming a part of the handleA of the racket and secured in a socket of the handle section 23 having a suitable hand grip 24; Inthe construction shown, members I8, I9 and 2li` are made of metal and the handle 23"of'wood'covered with the usual leather wrapping to form the grip 2li. The wood is machined' to fit closelyover the metal sections 2I and: 22 and may be bonded thereto with a heat curing cement. While this construction has proved to be satisfactory, alternative methods for applying the grips may be employed if desired, such as casting plastic material around the ends of the metal sections, or the metal sections may be. extended and ared tov form the Fig. 11 is a` grip. An encircling strengthening band 25 also may be employed Where the ends of the wood part ofV the handle terminate at the metal sections 2I and 22 of the frame. It will be appreciated that details of this nature are also subject to variation, and as such details d0 not relate directly to the invention, it will be unnecessary to elaborate on them further.

The inner loop section 2l) is provided with a series` of string openings, and adjacent pairs of these openings are connected by a series of curved tubular elements 26, 21, 28. These curved tubular elements constitute guides for Stringing the racket and bearings against whichthe string is tensioned. They are of several different-forms as will readily be seen from Fig. 1. Most of them have 180 bends, as, for example, elements 26 and 28, while others such as elements 21, have bends. The form of thesebearing elements also is adjusted to fit the final curvature of the inner perimeter of the frame. Where more than one bearing. element terminates at the same string opening, thatis, opposite the end of the same'string, they are slightly offset from one another, as clearly indicated in Figs. 14. and 15. This construction is'employed for example in the case of bearings. 26', 2S in Fig. 1.Y A similar oifset arrangement is employed in the case of the bearings Y26. 21 of Fig. 1, exceptk that in this instance the overlapping ends of the bearings lead respectively to a transverse string and a longitudinal stringY which intersect the frame in closely adjacent relationship.

The string openings, that is the openings in the inner loop section 20 which are to receive the'ends of the string bearing elements, may be formed in any. suitable manner, as for example by drilling or punching-the strip, preferably while the latter is dat, as shown in Fig. 5. The bearing elements are welded or brazed, or otherwise se cured, to the strip, for exampleby copper welding, and the projecting parts cleaned off by a milling operation. Then the ends of the tubular bearing elements are flared by drilling, spinning, peening or upsetting the metal so as to form smoothroundedentering portions, as shown at 29 in Fig. 3: This will avoid cutting or abrading of the strings while the racket is in use.

The sub-assembly of Figs. 5 and 6 as so formed is then accurately positioned in a bending jig and brought into the form of a hoop which defines the inner perimeter of the racket frame head. rIhis hoop is assembled with the curved frame members I8; I9 previously described, to which it is butt-welded or otherwise joined to form the tubular section illustrated in Fig. 3. The bearing elements 26, 21, 28, etc. may change their Shape slightly in the bending of strip 29 into its nal form, and if desired this may be compensated for by initially forming the bearing elements to allow for the slight change in their shape. It will be observed that strip 20 Vis made from stock of uniform width. Also, the curved members I8 and I9` may be formed from flat stock of uniform width. Therefore there is little or no Waste of the metal from which the frame is formed, and it is possible to employ more eX- pensive materials than would be the case if there were considerable Waste in the form of scrap. I recommend the use of a high strength steel alloy clad with a layer 0f non-tarnishing material such as copper or nickel, to protect the frame from corrosion and give it an attractive appearance.

My preferred throat construction is shown in Figs. 1 and 4. Gusset plates 3E! formed to iit the curvature of the inner edge of the throat portions of frame members I8, I9 and the adjacent portion of the frame member are welded to these members. As shown, these plates extend iiush with member 20 and slightly overlap the flanges of members I8, I9. Members I8, I9 may be buttwelded at 3l (Fig. '7) and the ends of member 20 may be butt-welded at 32 (Fig. 8).

A protective shoe 33 of rubber, plastic or other relatively soft and pliant material may be fastened to the nose of the racket, extending, say, three inches on each side of the longitudinal center line and covering approximately half of the tubular frame section. I have found that such shoes can be secured successfully by heat curing cements. For uses where injury to players may be sustained by accidental striking with the racket frame, as, for example, in the game of squash racquets, the protective shoe is extended to cover the entire perimeter of the racket head or any portion thereof which it is deemed necessary orV desirable to cover in such a manner in order to make the racket acceptable for use in enclosed courts.

The manner of Stringing the racket is indicated in the diagrams, Figs. 16 and 17. However this is simply one of the more conventional string arrangements and is subject to variation in accordance with any of the several systems employed by those versed in the art of racket Stringing.

In the modication illustrated in Figs. 9, 10 and 11, the frame is made of a seamless tube 34 provided with string openings around its inner perimeter as before. In this modification the sub-assembly described with reference to Figs. 5 and 6 is not employed. Instead the individual string bearing elements are inserted from outside the seamless tube. I have found that this can be accomplished by using bearing elements of the form shown at 35 in Fig. 9, having an elongated handle portion 36 by which it can be manipulated to bring it into its proper position within the tubular frame section. The element 35 is grasped by the handle portion 36 and threaded through one of the string openings by rst placing it` approximately in the position shown by the dotdash lines 36', Fig. 10. As the leading end of the bearing element is slid through the opening in the frame, the element is twisted around, being manipulated so as to bring it into the final position shown in Fig. 9. Then the short projecting end 31 is slightly. peened over or staked suiiciently to hold it in place, while the element 35 is welded or brazed to the frame after which both portions 36 and 31 are trimmed off iiush with the inner racket surface. The entering portions o-f the curved passageway formed by the tubular bearing element 35 may be rounded oli? by counter-boring, milling, grinding, or upsetting the metal to form a flared entering portion similar to that depicted at 29 in Fig. 3.

There are several Ways in which the ends of the strings may be anchored. Figs. 14 and 15 show my presently preferred method. The end 38 of the string is brought out close to another string already in place and in a direction parallel to the string. This end is knotted around the string as shown and pulled tight, forming a half hitch. The tension on the string pulls the end tightly against the frame, forming a secure anchorage. The adjacent bearings 26', 26" here illustrated may be oiset with their centers less than a diameter apart, in which case the Walls 0f the bearings will be cut away slightly to permit this close arrangement and bring the strings nearer together. That is, the strings will be nearer together than twice the wall thickness of the tubular bearing elements 26', 26".

While the special string bearings which I have described do much to eliminate string breakage, there will always be cases in which breakage will occur as for example where there is a weakness or defect in the string material or where the racket is misused, or due to other causes. In order to facilitate the repairing of broken strings, I prefer to use at selected points around the frame bearings 39 (Figs. 12 and 13) made of tubing large enough to allow two of the strings to pass through. The majority of breaks involve strings which pass through an area near the center of the racket. Consequently bearings 39 should be located somewhere near the midpoints of the sides and ends of the head of the racket and spaced so that repairs can be made by replacing only a small number of strings. The end of the old string O is looped around the new string N as at 40, and the new is looped around the old as at 4| These ends are secured in the same manner as the string ends shown in Figs. 14 and 15.

It will be appreciated that the features illustrated in Figs. 12 to 15 inclusive are applicable both to the seamless frame 34 therein shown and to the built-up form shown in Figs. 1 to 4 inclusive. In practicing my invention, I have constructed racket frames of conventional weights and balances which duplicate the playing qualities of rackets constructed by conventional methods from the finest ash wood and plastics laminations. My racket frames have margins in strength of materials suflicient that they should have long life under severe conditions of string tension and under the stress of normal play which produce high percentages of structural failures in frames of the best wooden construction nowv available.

The terms and expressions which I have employed are used in a descriptive and not :a limiting sense, and I have no intention of excluding such equivalents of the invention described, or of portions thereof, as fall within the purview of the claim.

I claim:

A racket frame of hollow tubular construction, the inner surface of the frame being constructed of a substantially nat strip having a series of string openings therein, string guides connecting adjacent pairs of said string openings, the outer part of the frame being constructed of members substantially U-shaped in cross-section, and the flat strip with its string guides being bent to form a closed loop and secured to the edges of the U-shaped members with said string guides disposed within the tubular frame thus formed.

CLARENCE A. LOIVELL.`

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,606,022 Gallaudet Nov. 9, 1926 2,230,177 Caines Jan. 28, 1941 2,456,023 Rosenbalm Dec. 14, 1948 FOREIGN PATENTS Number Country Date 212,195 Great Britain Mar. 6, 1924 234,324 Great Britain May 281, 1925 

